> We might be able to draw some smooth curve through these> points and point in the direction of evolution.>

I can't believe I am actually responding to this.

Evolution does not have a direction. Direction implies some idea of
where you are going and some implication that once started the
motion cannot be changed. Evolution is a random process of mutation and
selection. Just because an organism has gone so far in one direction
does not mean that you can extrpolate future developments.